Teeth, bone and skin cultured fibroblasts from patients with inherited connective tissue disorders such as osteogenesis imperfecta, dentinogenesis imperfecta and similar disorders are used as starting material for the extraction of collagen chains, glycosaminoglycans, phosphoproteins and other unit components with the objective of determining the chemical basis of these disorders. Material is selected on the basis of age, genetics and altered microscopic appearance and ultrastructure.